docs: def output_str(f):
      """Create a function that always return instances of `str`.
  
      This decorator is useful when the returned string is to be used
      with libraries that do not support ̀`unicode` in Python 2, but work
      fine with Python 3 `str` objects.
      """
      if six.PY2:
          #@functools.wraps(f)
          def new_f(*args, **kwargs):
              return f(*args, **kwargs).encode("utf-8")
      else:
          new_f = f
      return new_f